Cutting balloon catheter having flexible atherotomes

ABSTRACT

A cutting balloon catheter and method of making and using the same. The cutting balloon catheter may include a catheter shaft having a balloon coupled thereto. One or more cutting members or blades may be coupled to the balloon. The cutting members may configured to be more flexible.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/235,822, filed on Sep. 19, 2011, now U.S. Pat. No. 8,361,096, issuedJan. 29, 2013, which is a continuation of U.S. patent application Ser.No. 10/987,618, filed on Nov. 12, 2004, now U.S. Pat. No. 8,038,691,issued Oct. 18, 2011, the entire disclosure of which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention pertains to angioplasty and angioplasty ballooncatheters. More particularly, the present invention pertains toangioplasty balloon catheters that include one or more cutting edgescoupled to the angioplasty balloon.

BACKGROUND

Heart and vascular disease are major problems in the United States andthroughout the world. Conditions such as atherosclerosis result in bloodvessels becoming blocked or narrowed. This blockage can result in lackof oxygenation of the heart, which has significant consequences sincethe heart muscle must be well oxygenated in order to maintain its bloodpumping action.

Occluded, stenotic, or narrowed blood vessels may be treated with anumber of relatively non-invasive medical procedures includingpercutaneous transluminal angioplasty (PTA), percutaneous transluminalcoronary angioplasty (PTCA), and atherectomy. Angioplasty techniquestypically involve the use of a balloon catheter. The balloon catheter isadvanced over a guidewire so that the balloon is positioned adjacent astenotic lesion. The balloon is then inflated, and the restriction ofthe vessel is opened.

One of the major obstacles in treating coronary artery disease and/ortreating blocked blood vessels is re-stenosis. Evidence has shown thatcutting the stenosis, for example, with an angioplasty balloon equippedwith a cutting blade, during treatment can reduce incidence ofre-stenosis. Additionally, cutting the stenosis may reduce trauma at thetreatment site and/or may reduce the trauma to adjacent healthy tissue.Cutting blades may also be beneficial additions to angioplastyprocedures when the targeted occlusion is hardened or calcified. It isbelieved typical angioplasty balloons, alone, may not be able to expandcertain of these hardened lesions. Thus, angioplasty balloons equippedwith cutting edges have been developed to attempt to enhance angioplastytreatments. There is an ongoing need for improved angioplasty devices,including cutting angioplasty balloons, and improved methods of treatingintravascular stenoses and occlusions.

BRIEF SUMMARY

The present invention relates to angioplasty balloon catheters. In atleast some embodiments, an example balloon catheter may include acatheter shaft having a balloon coupled thereto. One or more cuttingmembers or blades may be coupled to the balloon. The cutting members maybe configured to be more flexible. These and other features aredescribed in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional side view of an example cuttingballoon catheter disposed in a blood vessel;

FIG. 2 is a partial perspective view of a cutting member and joiningmember for connecting the cutting member to a balloon in a manner thatallows the cutting member to have greater flexibility;

FIG. 3 is a perspective view of a portion of another example cuttingballoon catheter, showing an alternative arrangement for enhancing theflexibility of the cutting members;

FIG. 4 is a perspective view of another example cutting member;

FIG. 5 is a cutaway perspective view of a portion of the cutting membershown in FIG. 4 attached to a balloon;

FIG. 6 is an enlarged view of a portion of the cutting member attachedto the balloon as shown in FIG. 5, but where the cutting member isbroken at a selected location; and

FIG. 7 is a perspective view of another example cutting member.

DETAILED DESCRIPTION

The following description should be read with reference to the drawingswherein like reference numerals indicate like elements throughout theseveral views. The detailed description and drawings illustrate exampleembodiments of the claimed invention.

FIG. 1 is a partial cross-sectional side view of an example catheter 10disposed in a blood vessel 12 and positioned adjacent an intravascularlesion 14. Catheter 10 may include a balloon 16 coupled to a cathetershaft 18. One or more cutting members or blades 20 may be coupled toballoon 16. In general, catheter 10 may be advanced over a guidewire 22,through the vasculature, to a target area. Balloon 16 can then beinflated to expand lesion 14, and cutting members 20 may cut lesion 14.The target area may be within any suitable peripheral or cardiac vessellumen location.

Cutting members 20 may vary in number, position, and arrangement aboutballoon 16. For example, catheter 10 may include one, two, three, four,five, six, or more cutting members 20 that are disposed at any positionalong balloon 16 and in a regular, irregular, or any other suitablepattern. In general, cutting members 20 may be configured to haveenhanced flexibility. Increasing the flexibility of cutting members 20may desirably impact a number of characteristics and features ofcatheter 10. For example, increasing the flexibility may improve thetracking ability and general deliverability of catheter 10 through theoften tortuous anatomy. Additionally, increasing the flexibility mayallow catheter 10 to be navigable to a larger number of intravascularlocations, including some that may not be readily reachable by other,less flexible, cutting balloon catheters. In general, the enhancedflexibility is the result of a structural feature of cutting members 20or a structural modification to cutting members 20 or other componentsof catheter 10 that increases the flexibility of cutting members 20.Some examples of these features and modifications are described in moredetail below.

Balloon 16 may be made from typical angioplasty balloon materialsincluding polymers such as polyethylene terephthalate (PET),polyetherimid (PEI), polyethylene (PE), etc. Some other examples ofsuitable polymers, including lubricious polymers, may includepolytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE),fluorinated ethylene propylene (FEP), polyoxymethylene (POM),polybutylene terephthalate (PBT), polyether block ester, polyurethane,polypropylene (PP), polyvinylchloride (PVC), polyether-ester (forexample, a polyether-ester elastomer such as ARNITEL® available from DSMEngineering Plastics), polyester (for example, a polyester elastomersuch as HYTREL® available from DuPont), polyamide (for example,DURETHAN® available from Bayer or CRISTAMID® available from ElfAtochem), elastomeric polyamides, block polyamide/ethers, polyetherblock amide (PEBA, for example, available under the trade name PEBAX®),silicones, Marlex high-density polyethylene, Marlex low-densitypolyethylene, linear low density polyethylene (for example, REXELL®),polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide(PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propylvinyl ether) (PFA), other suitable materials, or mixtures, combinations,copolymers thereof, polymer/metal composites, and the like. In someembodiments, it may be desirable to use high modulus or generallystiffer materials so as to reduce balloon elongation. The above list ofmaterials includes some examples of higher modulus materials. Some otherexamples of stiffer materials include polymers blended with liquidcrystal polymer (LCP) as well as the materials listed above. Forexample, the mixture can contain up to about 5% LCP.

Balloon 16 may be configured so that it includes one or more “wings” orwing-shaped regions when balloon 16 is deflated. These wings may appearas a plurality of alternating inward and outward radial deflections inballoon 16 when balloon 16 is deflated. These wings may be desirable fora number of reasons. For example, by including balloon 16 with wings,balloon 16 may have more predictable and consistent re-foldingcharacteristics. Additionally, the wings may be configured so thatcutting members 20 can be positioned at the inward-most positions of thedeflated balloon 16. This arrangement allows cutting members 20 to bepositioned more closely to shaft 18 when balloon 16 is deflated.Accordingly, cutting members 20 can be moved away from the vessel wallswhere they might otherwise result in contact and, possibly, damage tohealthy tissue during movement of catheter 10 within a body lumen.Additionally, alternating the wings and cutting members 20 as well aspositioning cutting members 20 relatively close to shaft 18 may allowthe wings to fold over and cover cutting members 20 when balloon 16 isdeflated. Again, this feature may reduce the exposure of cutting members20 to the blood vessel.

Shaft 18 may be a catheter shaft, similar to typical catheter shafts.For example, shaft 18 may include an inner tubular member 24 and outertubular member 26. Tubular members 24/26 may be manufactured from anumber of different materials. For example, tubular members 24/26 may bemade of metals, metal alloys, polymers, metal-polymer composites or anyother suitable materials. Some examples of suitable metals and metalalloys include stainless steel, such as 300 series stainless steel(including 304V, 304L, and 316L; 400 series martensitic stainless steel;tool steel; nickel-titanium alloy such as linear-elastic orsuper-elastic Nitinol, nickel-chromium alloy, nickel-chromium-ironalloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having acomposition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe,a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum0.15% Si), hastelloy, monel 400, inconel 825, or the like; or othersuitable material. Some examples of suitable polymers include thosedescribed above in relation to balloon 16. Of course, any other polymeror other suitable material including ceramics may be used withoutdeparting from the spirit of the invention. The materials used tomanufacture inner tubular member 24 may be the same as or be differentfrom the materials used to manufacture outer tubular member 26. Thosematerials listed herein may also be used for manufacturing othercomponents of catheter 10 including cutting members 20.

Tubular members 24/26 may be arranged in any appropriate way. Forexample, in some embodiments inner tubular member 24 can be disposedcoaxially within outer tubular member 26. According to theseembodiments, inner and outer tubular members 24/26 may or may not besecured to one another along the general longitudinal axis of shaft 18.Alternatively, inner tubular member 24 may follow the inner wall orotherwise be disposed adjacent the inner wall of outer tubular member26. Again, inner and outer tubular members 24/26 may or may not besecured to one another. For example, inner and outer tubular members24/26 may be bonded, welded (including tack welding or any other weldingtechnique), or otherwise secured at a bond point. In some embodiments,the bond point may be generally disposed near the distal end of shaft18. However, one or more bond points may be disposed at any positionalong shaft 18. The bond may desirably impact, for example, thestability and the ability of tubular members 24/26 to maintain theirposition relative to one another. In still other embodiments, inner andouter tubular member 24/26 may be adjacent to and substantially parallelto one another so that they are non-overlapping. In these embodiments,shaft 18 may include an outer sheath that is disposed over tubularmembers 24/26.

Inner tubular member 24 may include an inner lumen 28. In at least someembodiments, inner lumen 28 is a guidewire lumen. Accordingly, catheter10 can be advanced over guidewire 22 to the desired location. Theguidewire lumen may extend along essentially the entire length ofcatheter shaft 18 so that catheter 10 resembles traditional“over-the-wire” catheters. Alternatively, the guidewire lumen may extendalong only a portion of shaft 18 so that catheter 10 resembles“single-operator-exchange” or “rapid-exchange” catheters. Regardless ofwhich type of catheter is contemplated, catheter 10 may be configured sothat balloon 16 is disposed over at least a region of inner lumen 28. Inat least some of these embodiments, inner lumen 28 (i.e., the portion ofinner lumen 28 that balloon 16 is disposed over) may be substantiallycoaxial with balloon 16.

Shaft 18 may also include an inflation lumen 30 that may be used, forexample, to transport inflation media to and from balloon 16. Thelocation and position of inflation lumen 30 may vary, depending on theconfiguration of tubular members 24/26. For example, when outer tubularmember 26 is disposed over inner tubular member 24, inflation lumen 30may be defined within the space between tubular members 24/26. Moreover,depending on the position of inner tubular member 24 within outertubular member 26, the shape of lumen 30 (i.e., the shape adjacent shaft18) may vary. For example, if inner tubular member 24 is attached to ordisposed adjacent to the inside surface of outer tubular member 26, theninflation lumen 30 may be generally half-moon in shape; whereas if innertubular member 24 is generally coaxial with outer tubular member 26,then inflation lumen 30 may be generally ring-shaped or annular inshape. It can be appreciated that if outer tubular member 26 is disposedalongside inner tubular member 24, then lumen 30 may be the lumen ofouter tubular member 26 or it may be the space defined between the outersurface of tubular members 24/26 and the outer sheath disposedthereover.

Balloon 16 may be coupled to catheter shaft 18 in any of a number ofsuitable ways. For example, balloon 16 may be adhesively or thermallybonded to shaft 18. In some embodiments, a proximal waist 32 of balloon16 may be bonded to shaft 18, for example, at outer tubular member 26,and a distal waist 34 may be bonded to shaft 18, for example, at innertubular member 24. The exact bonding positions, however, may vary. Itcan be appreciated that a section of proximal waist 32 may not havesections 36 extending therefrom in order for suitable bonding betweenballoon 16 and outer tubular member 30.

In addition to some of the structures described above, shaft 18 may alsoinclude a number of other structural elements, including those typicallyassociated with catheter shafts. For example, shaft 18 may include aradiopaque marker coupled thereto that may aid a user in determining thelocation of catheter 10 within the vasculature. In addition, catheter 10may include a folding spring (not shown) coupled to balloon 16, forexample, adjacent proximal waist 32, which may further help in balloonfolding and refolding. A description of a suitable folding spring can befound in U.S. Pat. No. 6,425,882, which is incorporated herein byreference.

As described above, cutting members 20 may be configured to haveincreased flexibility. Increasing the flexibility of cutting members 20may occur in a number of different manners. For example, a flexiblejoining member 38 may be coupled to cutting member 20 and to balloon 16as shown in FIG. 2 (and depicted in an exploded view). Joining member 38may be formed from a generally flexible or soft material that allows theinterface between cutting member 20 and balloon 16 to be somewhatelastic or pliable. For example, joining member 38 may be manufacturedfrom a low durometer polyurethane or any other suitable material(including any of the polymers and other materials disclosed herein).Accordingly, cutting member 20 may be able to move laterally about eightdegrees or less. In addition, different portions of cutting member 20may be able to bend or flex, while other portions remain essentiallyunchanged.

In at least some embodiments, joining member 38 can be attached to anddisposed between cutting member 20 and balloon 16. For example, joiningmember 38 can be attached to an outer surface 40 of balloon 16 and to abase 42 of the cutting member 20. The attachment of joining member 38with cutting member 20 and balloon 16 may be achieved in any appropriatemanner, such as by adhesive bonding, casting, thermal bonding,mechanically connecting, welding, brazing, and the like, or in any othersuitable way. The attachment means need not be the same for theattachment between cutting member 20 and joining member 38 as the meansused to attach balloon 16 and joining member 38.

FIG. 3 depicts a partial perspective view of another catheter 110 thatis similar to catheter 10. Catheter 110 includes cutting members 120that are disposed about balloon 16 in pairs that are arranged in tandem.This embodiment may increase the flexibility of cutting members 120 bydividing what might otherwise be a single cutting blade into multipleparts or segments. Thus, the segmented cutting members 120, by virtue oftheir shortened length, are more amenable to bending or flexing. Inaddition, the flexibility of cutting members 120 may be increased byincluding joining member 38. It can be appreciated that the precisearrangement of cutting members 120 is not intended to be limited tobeing in tandem. For example, pairs of cutting members 120 may have anarrangement that is longitudinally offset. Moreover, catheter 110 is notintended to be limited to just pairs of cutting members 120, as anysuitable number of cutting members 120 may be used without departingfrom the spirit of the invention.

It can also be seen in FIG. 3 that cutting members 120 may also includea series of alternating tabs 144 and holes or openings 146 that aredisposed along the base 142 of cutting members 120. Tabs 144 andopenings 146 may have a number of functions. For example, openings 146(or, more precisely, the portions of cutting member 120 adjacentopenings) may provide a location for adhesive (e.g., polyurethane or anyother suitable material) to flow into so as to improve the bonding ofcutting member 120 with balloon 16. This bonding media may encapsulatethe base 142 of cutting member 120. In addition, tabs 144 and openings146 may also desirably impact the flexibility of cutting member 120. Theshape, size, and number of tabs 144 and opening 146 may vary. Forexample, tabs 144 may have a shape similar to an inverted T (when viewedfrom the side) or otherwise have a splayed pillar-like shape, andopenings 146 may be somewhat rounded or oval. It can be appreciated,however, that tabs 144 and openings 146 are not intended to be limitedto these or any other particular shape. Additionally, the size andnumber of tabs 144 and openings 146 may also vary, typically in relationto the length of cutting members 120. For example, openings 146 may havea height in the range of about 0.002 to about 0.010 inches or so and awidth in the range of about 0.007 to about 0.015 inches or so.

FIG. 4 illustrates another example cutting member 320 that can be usedwith any of the catheter embodiments disclosed herein or any othersuitable balloon catheter device, including those with joining member38. Cutting member 320 is similar to any of the other cutting membersdisclosed herein except that a slot 348 is formed along or adjacent thecutting edge 350.

By including slot 348, cutting member 320 may have increased flexibilityby defining a region that is thinned or narrowed. Additionally, becauseslot 348 is formed in cutting member 320 it can be appreciated that slot348 creates an increase in flexibility that is localized within thecutting member 320 itself. This feature may be desirable for a number ofreasons. For example, because the increase in flexibility is localizedwithin cutting member 320, the desired flexibility characteristics canbe incorporated into essentially any cutting balloon catheter by simplysubstituting cutting member 320 for the cutting blade used on theexisting balloon catheter.

Another desirable feature of slot 348 is that slot 348 may cause a flexpoint F of cutting member 320 to be located at or near the bottom orbase 342 of cutting member 320. In some embodiments, base 342 may befully encapsulated within polyurethane or another suitable adhesive ortransition material 352 as shown in FIG. 5. Transition material 352 maybe made from any suitable material (including those disclosed herein)and may function as an attachment means for attaching cutting member 320to balloon 16. In some embodiments, transition material 352 may bejoining member 38 or any other suitable structure, while in otherembodiments, transition material 352 may be used alone or in combinationwith joining member 38.

Breaks that might occur within cutting member 320 during use or deliverycan be isolated at the bottom of the flex point F and, thus, the bottomof cutting member 320. Therefore, transition material 352 at the base342 of cutting member 320 can surround the broken segments 354 ofcutting member 320 and shield balloon 16, other portions of thecatheter, and surrounding tissue from unintentional damage as shown inFIG. 6. It can be appreciated that if cutting member 320 were to break,the flexibility of the broken cutting member 320 would be greater thanwhen intact. Thus, the shielding feature provided by encapsulatingbroken segments 354 in a polyurethane transition material 352 at base342 of cutting member may be utilized by the clinician to furtherenhance the flexibility of cutting member 320. For example, theclinician may be able to intentionally break cutting member 320 in orderto increase flexibility to an even greater extent, while maintainingconfidence that broken segments 354 of cutting member 320 are properlycontained and shielded.

As the length of cutting member 320 (or other cutting member disclosedherein) changes, the number and position of slots 348 may vary. Forexample, the length of any of the cutting members disclosed herein mayrange from about 4 millimeters to about 20 millimeter or so. Generally,as the length increases, the number of slots that may be desirableincreases. Accordingly, relatively short cutting members (e.g., about4-7 millimeters or so) may not have any slots. Slightly longer cuttingmembers (e.g., about 7-14 millimeters or so) may include one slotsimilar to slot 348 in cutting member 320. Even longer cutting members(e.g., about 12 millimeters or longer) may include more than one slot.For example, FIG. 7 illustrates cutting member 420 that has two slots448 a/b disposed along cutting edge 450. Of course, a number of additionembodiments of cutting members are contemplated that have a variety oflengths and numbers of slots.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of theinvention. The invention's scope is, of course, defined in the languagein which the appended claims are expressed.

What is claimed:
 1. A cutting balloon catheter, comprising: an elongatecatheter shaft; an inflatable balloon coupled to the catheter shaftproximate a distal end of the catheter shaft; a flexible joining membermounted on the balloon; and a cutting member having a slot formedtherein dividing a cutting edge of the cutting member into a firstcutting edge portion and a second cutting edge portion discontinuouswith the first cutting edge portion, the slot defining a flex point ofthe cutting member between the first cutting edge portion and the secondcutting edge portion, the cutting member being constructed of a singlecontinuous piece of material forming the first cutting edge portion, thesecond cutting edge portion, and the flex point; wherein the flex pointextending between the first cutting edge portion and the second cuttingedge portion is embedded within the flexible joining member; and whereinthe flex point is configured to be intentionally broken during use suchthat the first cutting edge portion is split from the second cuttingedge portion to increase the flexibility of the cutting member.
 2. Thecutting balloon catheter of claim 1, wherein after breaking the flexpoint during use the flex point includes first and second brokensegments configured to remain encapsulated within the flexible joiningmember.
 3. The cutting balloon catheter of claim 1, wherein at least aportion of the slot is embedded within the flexible joining member. 4.The cutting balloon catheter of claim 1, wherein the flexible joiningmember includes a polymeric material.
 5. The cutting balloon catheter ofclaim 1, wherein the cutting member includes a base portion includingalternating tabs and holes embedded in the flexible joining member. 6.The cutting balloon catheter of claim 5, wherein the alternating tabsand holes provide interlocking engagement with the flexible joiningmember.
 7. The cutting balloon catheter of claim 1, wherein the elongatecatheter shaft includes an inner tubular member and an outer tubularmember surrounding the inner tubular member.
 8. The cutting ballooncatheter of claim 7, wherein a proximal waist of the inflatable balloonis affixed to the outer tubular member and a distal waist of theinflatable balloon is affixed to the inner tubular member.
 9. A cuttingballoon catheter, comprising: an elongate catheter shaft; an inflatableballoon coupled to the catheter shaft proximate a distal end of thecatheter shaft; a flexible joining member mounted on the balloon; and acutting member having a slot formed therein dividing a cutting edge ofthe cutting member into a first cutting edge portion and a secondcutting edge portion discontinuous with the first cutting edge portion,the slot defined by a bridge of material of the cutting member betweenthe first cutting edge portion and the second cutting edge portion, thecutting member being constructed of a single continuous piece ofmaterial forming the first cutting edge portion, the second cutting edgeportion, and the bridge of material; wherein the bridge of materialextending between the first cutting edge portion and the second cuttingedge portion is embedded within the flexible joining member; and whereinthe bridge of material is configured to be intentionally broken into afirst broken segment and a second broken segment during use to increasethe flexibility of the cutting member.
 10. The cutting balloon catheterof claim 9, wherein the first and second broken segments are configuredto remain encapsulated within the flexible joining member.
 11. Thecutting balloon catheter of claim 10, wherein at least a portion of theslot is embedded within the flexible joining member.
 12. The cuttingballoon catheter of claim 9, wherein the flexible joining memberincludes a polymeric material.
 13. The cutting balloon catheter of claim9, wherein the cutting member includes a base portion includingalternating tabs and holes embedded in the flexible joining member. 14.The cutting balloon catheter of claim 13, wherein the alternating tabsand holes provide interlocking engagement with the flexible joiningmember.
 15. The cutting balloon catheter of claim 9, wherein theelongate catheter shaft includes an inner tubular member and an outertubular member surrounding the inner tubular member.
 16. The cuttingballoon catheter of claim 15, wherein a proximal waist of the inflatableballoon is affixed to the outer tubular member and a distal waist of theinflatable balloon is affixed to the inner tubular member.